Nonconductive films for lighter than air balloons

ABSTRACT

Non-conductive films for constructing lighter than air balloons are provided. A non-conductive film may comprise multiple layers of gas barrier polymers. An outer surface printable layer and an interior heat or ultrasonically sealable layer may also be included. Each gas barrier film may comprise multiple (e.g., from 3 to approximately 75) barrier layers. A gas barrier core has a nano-layer structure. A gas barrier core may also comprise a biodegradable film or a bio-based film. A non-conductive film may comprise a metal layer for enhancing gas barrier properties. The metal layer may be discontinuous. The metal layer may be conductive and coated with an insulating top coat.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 14/067,878, filed Oct. 30, 2013, titled “Nonconductive Filmsfor Lighter Than Air Balloons,” the content of which is incorporatedherein by reference in its entirety.

TECHNICAL FIELD

The present invention relates generally to lighter than air balloons,and more particularly, some embodiments relate to non-conductive filmsfor lighter than air balloons.

DESCRIPTION OF THE RELATED ART

Lighter than air balloons are popular and have many usages around theworld such as toys, advertising media, articles in displays, etc.Lighter than air balloons are filled with lighter than air gases andremain aloft due to its buoyancy. Lighter than air balloons are made ofmaterials that have gas barrier properties. Materials having gas barrierproperties may prevent ingress and egress of gas thereby maintaining thelighter than air balloons afloat. Most of lighter than air balloons aremade of materials that are electrically conductive. Lighter than airballoons may be released under supervision for various purposes.However, accidental releases may be inevitable. Released balloons maybecome entangled at different structures such as buildings, trees, orpower transmission lines. The conductivity of the materials may causepower outages and service disruption to users, causing a negative impactto the users and economical losses.

BRIEF SUMMARY OF THE INVENTION

According to various embodiments of the invention, non-conductive filmsare provided. The non-conductive films may be used to construct lighterthan air balloon envelopes. Various embodiments comprise multiple layersof gas barrier polymers. An outer surface printable layer and aninterior heat or ultrasonically sealable layer may also be included.Each gas barrier film may comprise multiple (e.g., from 3 toapproximately 75) barrier layers. In one embodiment, a gas barriercomprises from 5 to 27 barrier layers. In one embodiment, the gasbarrier core has a nano-layer structure. Various embodiments comprise abio-degradable film or a bio-based film. Further embodiments maycomprise a metal layer for enhancing gas barrier properties. The metallayer may be conductive and coated with an insulating top coat. Otherembodiments may comprise a metallization layer having patterned ordiscontinuous metal patches.

Other features and aspects of the invention will become apparent fromthe following detailed description, taken in conjunction with theaccompanying drawings, which illustrate, by way of example, the featuresin accordance with embodiments of the invention. The summary is notintended to limit the scope of the invention, which is defined solely bythe claims attached hereto.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention, in accordance with one or more variousembodiments, is described in detail with reference to the followingfigures. The drawings are provided for purposes of illustration only andmerely depict typical or example embodiments of the invention. Thesedrawings are provided to facilitate the reader's understanding of theinvention and shall not be considered limiting of the breadth, scope, orapplicability of the invention. It should be noted that for clarity andease of illustration these drawings are not necessarily made to scale.

FIGS. 1A-1C illustrate constructions of prior art conductive balloonenvelopes.

FIG. 2 illustrates an exemplary non-conductive balloon film inaccordance with an embodiment of the present application.

FIG. 3 illustrates an exemplary 7-layer non-conductive balloon films inaccordance with various embodiments of the present application.

FIGS. 4A-4B illustrate exemplary 9-layer non-conductive balloon films inaccordance with various embodiments of the present application.

FIGS. 5A-5B illustrated exemplary 11-layer non-conductive balloon filmsin accordance with various embodiments of the present application.

FIGS. 6A-6C illustrate exemplary balloon films having a barrier corewith a nano-layer structure in accordance with various embodiments ofthe present application.

FIG. 7 illustrates an exemplary balloon film 700 having a barrier corehaving multiple sub-barrier cores, where each of the sub-barrier corehas a nano-layer structure in accordance with an embodiment of thepresent application.

FIG. 8 illustrates an exemplary non-conductive balloon film inaccordance with an embodiment of the present application.

FIGS. 9A-9E illustrated exemplary non-conductive balloon films inaccordance with various embodiments of the present application.

FIG. 10 illustrates an exemplary non-conductive film in accordance withan embodiment of the present application.

FIGS. 11A-B illustrate exemplary non-conductive balloon films inaccordance with various embodiments of the present application.

The figures are not intended to be exhaustive or to limit the inventionto the precise form disclosed. It should be understood that theinvention can be practiced with modification and alteration, and thatthe invention be limited only by the claims and the equivalents thereof.

DETAILED DESCRIPTION OF THE INVENTION

Most existing balloons are made of oriented polyester (PET) or orientedNylon (OPA) films. The films may be single-layer or multiple-layer.Conventionally, lighter-than-air balloons are usually constructed ofelectrically conductive materials such as metallized Biaxially-orientedpolyethylene terephthalate (“BoPET” or “Mylar”.) The films aremetallized to enhance the gas barrier properties and are often coatedwith a heat sealant to permit forming of the balloon. The balloonenvelope is made by sealing, such as heat sealing peripheral portions ofpanels made of the above material while in a two dimension lay-flat formto any desired two-dimensional shape. The material can be anonelastomeric polymer sheet carrying a continuous metal layer on atleast one surface. PET and Nylon films are known to be very susceptibleto pinhole formation in flexing (e.g., folding, creasing, or forminginto pouches), which may cause a significant loss of gas barrierproperties and greatly reduce a balloon's flight time.

FIGS. 1A-1C illustrate constructions of prior art conductive balloonenvelopes 110, 120, and 130. A metal layer (e.g., a thin metal foil suchas an aluminum layer) may be laminated to or vacuum deposited directlyon a film surface (e.g., an oriented Nylon film or a PET film.) The thinmetal layer is impermeable to the lighter than air gas, whereas thelayer of the nonelastomeric polymer provides structural integrity forthe metal as well as limiting diffusion from pinholes or imperfectionsthat may exist in the continuous metal layer. These materials have aconductive surface.

Non-surface conductive laminations remain conductive as long as thestructure comprises a continuous layer of metal. For example, twocontinuous nonelastomeric films having a continuous layer of vapordeposited metal sandwiched therebetween may be used. This composite maybe so produced by vapor depositing the metal layer on either layer ofthe nonelastomeric polymer film and subsequently laminating theremaining layer of nonelastomeric film to the vapor deposited metallayer. These laminated structures may have a low surface conductivitydue to the nonconductive outer polymeric layers. However, as long as themetal layer is continuous, the lamination functions as a capacitorstoring charges. The balloon can become electrically conductive underhigh electrical field strengths due to an electrical breakdown of thenonelastic films included in the balloon film.

FIG. 2 illustrates an exemplary non-conductive film 200 in accordancewith an embodiment of the present application. The non-conductive film200 may be used to make a lighter than air balloon envelope. Theillustrated non-conductive balloon film 200 is a 7-layer coextrudedfilm. In one embodiment, each film may be 12 to 78 microns thick (0.5 to3 mils.) The exemplary non-conductive balloon film 200 comprisesmultiple layers: a polyolefin layer 202, a first adhesive layer 204, afirst gas barrier layer 206, an Ethylene vinyl alcohol (“EVOH”) gasbarrier layer 208, a second gas barrier layer 210, a second adhesivelayer 212, and a heat sealing layer 214. The film 200 comprises a gasbarrier core 216. The gas barrier core 216 may comprise a set ofpolymeric gas barrier layers. In the illustrated example, the first gasbarrier layer 206, the EVOH layer 208, and the second gas barrier layer210 create the gas barrier core 216. Each polymeric gas barrier layerhas a first surface and a second surface.

Each layer of the gas barrier core 216 may be selected to control thegas barrier properties of the film 200. For example, the first gasbarrier layer 206 and the second gas barrier layer 210 may be nylon(e.g., Nylon 66, Nylon 6, Nylon MDX6, Nylon 6,10 or an amorphous nylon.)The material for the first gas barrier 206 or the second gas barrier 210may be selected according to the gas barrier core 216, compatibilitywith the EVOH used in the EVOH layer 208, and flex crack resistance. TheEVOH may be selected from various grades of copolymer with varyingethylene contents based on the gas barrier levels of the EVOH for thefilm 200. For the gas barrier core 216 of the illustrated example, theEVOH layer 208 is sandwiched between the first gas barrier 206 and thesecond gas barrier 210.

In other embodiments, a gas barrier core may have a structure such thata nylon barrier layer is sandwiched between a first EVOH layer and asecond EVOH layer. The gas barrier core may be constructed withalternating EVOH layers and nylon layers. The total number of the EVOHand the nylon layers may vary thereby affecting the physical and barrierproperties of a non-conductive film such as the film 200. The use ofnylon layers in combination with the EVOH layers enhances the overallgas barrier properties of the film 200 due to the inherent gas barriercharacteristics of the nylon material. In addition, this structure mayfurther improve the EVOH durability. The nylon materials included mayselectively absorb moisture from the film 200 acting as a desiccant forthe EVOH and maintaining the superior gas barrier property of the EVOH.

The illustrated exemplary non-conductive film 200 comprises a firstsurface that is the polyolefin layer 202 and a second surface that isthe heat sealing layer 214. The polyolefin layer 202 may be used fordecoration purposes and the heat sealing layer 214 may form an enclosedballoon envelope. The polyolefin layer 202 may be a functionalizedpolymer or a mix of polymers. The polyolefin layer 202 may befunctionalized by a variety of surface treatment methods (e.g., corona,flame, atmospheric plasma, or chemical treatment), which may enhance thesurface receptivity to decorative methods such as inks, coatings, ormetal layers. The first adhesive layer 204 affixes the gas barrier core216 to the polyolefin layer 202. The second adhesive layer 212 affixesthe gas barrier core 216 to the heat sealing layer 214.

In various embodiments, the first adhesive layer 204 may be differentfrom the second adhesive layer 212 as the surfaces of the barrier core216 may be made of different polymers. In various embodiments, therelative bond strengths required for affixing the gas barrier core 216to the first surface (i.e., the polyolefin layer 202) and the secondsurface (i.e., the heat sealing layer 214) may be different due to thefact that the first surface and the second surface may be of differentmaterials. Depending on the relative bond strengths desired of anon-conductive film 200, the first adhesive layer 204 and the secondadhesive layer 212 may be the same or different. In various embodiments,the first adhesive layer 204 and the second adhesive layer 212 each maycomprise multiple layers as a single bonding layer composition may beinadequate to affix the barrier core 216 to either the polyolefin layer202 or the heat sealing layer 214.

Various embodiments may comprise a decoration layer. In someembodiments, the polyolefin layer may be the decoration layer. Thepolyolefin layer 202 may be selected according to the decoration methodto be used. It may be selected as such to be resistant to abrasion,puncture, surface slip and/or antiblocking properties. The polyolefinlayer 202 may carry an opaque pigment, a transparent color, or tint, andmay be receptive to metal deposition or solution and emulsion coating.Decorations may be applied to the interior surface of the polyolefinlayer 202 by lamination. In further embodiments where the polyolefinlayer 202, the first adhesive layer 204, the gas barrier core 216, andthe second adhesive layer are transparent, decorations may be applied tothe heat sealing layer 214.

The surface polyolefins are selected to enhance heat sealing propertiesand graphic art properties to permit decorative images and messages tobe applied to the balloon envelope. The decoration layer may beconstructed of a resin material. Exemplary resin materials includepolyolefin resins, copolymers of polyolefins (e.g., polyethylene,polypropylene, copolymers of polyethylene with minor amounts of otherC4-10 olefins, particularly C4-8 polyolefins), or polymer resins (e.g.polyamides, polyesters, copolymers of ethylene and vinyl alcohol and thelike.) Polyethylenes may include HPLDPE resins, or LLDPE resins having adensity of from about 0.925 to about 0.945 g/cm³. Polymers may includepolypropylenes, preferably isotactic, having a density of from about0.89 to about 0.91 g/cm³. The polyolefin layer 202 may include any ofseveral anti-cling, slip or anti-block additives (e.g., silicas, talcs,diatomaceous earth, silicates, or lubricants) to improve the slipcharacteristics of the layer. These additives are generally blended withthe resin material in a predetermined amount (e.g., from about 100 toabout 20,000 ppm.)

The heat sealable outer layer 214 allows the non-conductive balloon filmto form a gas tight seal by heat or ultrasonic sealing of the balloonenvelope. The heat sealable outerlayer 214 may be made of a resin suchas polypropylene (PP), ethylene propylene copolymers, low densitypolyethylene (LDPE), linear low density polyethylene (LLDPE), mediumdensity polyethylene (MDPE), high density polyethylene (HDPE),metallocene-catalyzed polyethylene (mPE), very low density polyethylene(VLDPE), or ultralow density polyethylene (ULDPE). The resin may also beblended to achieve a desired range of sealing, hot tack, physical ormechanical properties of the final film product. Homopolymers,terpolymers, or copolymers of ethylene and alpha-olefins such asmetallocene catalyzed linear low density polyethylene (mLLDPE) may alsobe used. In various embodiments of copolymers, the weight percentage ofthe alpha-olefins resins may range between 4 and 15% (e.g., from 6 to12% or from 6 to 10%) by weight. Alpha-olefin comonomers includepropylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, and1-octene may also be used. The alpha-olefins range from about C3 to C20(e.g., from C3 to C10, or from C3 to C8.)

Some embodiments may comprise a metal layer. The metal layer may bevapor deposited and used for graphic or gas barrier purposes. The metallayer may be applied by various deposition methods such as vapordeposition, sputtering, electron beam evaporation, printing or coatingusing a reflective metal bearing ink and deposition using wet depositionsystems using silver and copper bearing solutions mixed with a reducingagent to produce a silver or copper deposition on a surface. The metallayer may be coated with a non-sealable and non-conductive polymericovercoating.

In various embodiments, the polymeric overcoating may be added by anin-chamber coating process. The monomeric materials utilized may berelatively low in molecular weight, between 150 and 1000, and preferablyin the range 200 to 300. In one embodiment, polyfunctional acrylates ormixtures of monofunctional acrylates and polyfunctional acrylates areused. In various embodiments, the monomers or monomer mixtures have anaverage of about two or more double bonds (i.e., a plurality of olefinicgroups) and have vapor pressure in the range of 1.times.10.sup.-6 Ton to1.times.10.sup.-1 Torr at standard temperature and pressure, (i.e.,relatively low boiling materials). In one embodiment, the monomers ormonomer mixtures have a vapor pressure of approximately 10.sup.-2 Torrat standard temperature and pressure. These high-vapor-pressure monomerscan be flash vaporized at relatively low temperatures and thus are notdegraded (cracked) by the heating process. The deposited monomer isreactive and cures to form an integral film when exposed to a radiationsource. Accordingly, a substantially continuous coating is provided eventhough the deposited film may be very thin.

A vacuum chamber may be evacuated until the pressure is less than1.times.1.sup.-1 Torr and preferably 1.times.10.sup.-5 Torr. In variousembodiments, the vacuum chamber includes a substrate support such as arotating drum. The support may be removable or interchangeable and has asurface of which the temperature is maintained sufficient to permitcondensation onto the metallized substrate surface of a material that isbeing deposited thereon. The temperature may be in the range of 40° C.to 70° C., depending on the monomer or the monomer mixture used. Thecurable monomer may be metered to a heated flash vaporizer system wherethe material is atomized, vaporized, and condensed on the surface of themovable metallized film, which travels at a speed between 1 and 1000 cmper second. In one embodiment, the vapor outlet of a flash vaporizer andthe curing means may be mounted such that the metalized film is exposedto the flash vaporizer prior to being treated by the curing means. Thecuring is accomplished by opening the double bonds of the reactantmolecules, such as by using an energy source (e.g., an apparatus thatemits infra-red, electron beam, thermionic, or ultra violet radiation.)The condensed film is less than 4 microns thick.

In other embodiments, the metal layer may be coated with anon-conductive film layer such as via an out of line solution, emulsion,extrusion coating or related printing process, a spray coating processor by adhesive, thermal or extrusion lamination process.

In various embodiments, the metallized film is unwound (e.g., bytension) and guided into a coating machine. The coating machine mayclean or pretreat the metal surface to aid adhesion of subsequentlyapplied coatings. The metallized film may subsequently pass a coatingstation where the coating solution or ink is applied. The coatingsolution or ink may be applied by the coating and printing methods suchas direct or indirect gravure, air knife coating, Myer rod coating,spray coating or the like. The surface of the coated metallized film mayfurther be dried by a method suitable for the applied coating or ink.

The metallized film may be placed on an unwind station close to thecoating station such that the metal surface is not contacted by theroller surfaces prior to the nip point. A separate extruder may be usedto prepare a continuous supply of the molten polymer (e.g., LDPE) to beused as a coating layer. The metallized film is unwound, passed into theextrusion coater, passed over a nip roller, and pressed against atemperature-controlled roller adjacent to the nip. With the nip closed,the molten LDPE coating is extruded from a die as a thin moltenmembrane. The thin molten membrane may be dropped between the metallizedfilm and the temperature controlled roll surface, which are adheredtogether at the nip point. The coated film may be cooled by atemperature controlled roller to a uniform temperature. The coated filmmay be subsequently wound into rolls to create balloons. In variousembodiments, the coated LDPE layer may be opaque, clear, or pigmented.

In another embodiment, a laminating film, that is, a film to belaminated onto the metallized surface may be placed on a separate unwindstation. The laminating film and the metallized film may besimultaneously unwound and passed into the laminator. Applying anadhesive, the two films may be adhered together by the laminationadhesive at a nip. The lamination adhesive may be a one or two partadhesive. In one embodiment, a one-part adhesive is diluted with solventand applied to the lamination films. In another embodiment, a two partadhesive is mixed and applied to the lamination film. The laminationprocess continues with the film being passed through a curing oven andheated to initiate the adhesives curing reaction and cooled. Thelamination adhesive may be a multiple layer coextrusion designed toenhance lamination adhesion and/or barrier properties.

In a further embodiment, a thermal laminating film, that is, the film tobe thermally laminated to the metallized surface is placed on a separateunwind station. The thermal laminating film is passed over atemperature-controlled roller adjacent to the laminating nip to activatethe thermal adhesive layer. The metallized film is passed over thelaminating nip. With the laminating nip closed, the thermally activatedadhesive is pressed against the metal surface of the metallized film toform a bond. The lamination continues with the film being passed aroundthe temperature controlled roller and subsequently to a secondtemperatures controlled roll cool the thermally laminated film to auniform temperature.

In further embodiments, a reflective film may be applied to or depositedon an outer surface of the non-conductive film such as the decorationlayer 202. The reflective film may be discontinuous or patterned metal.The patterned vapor deposition may enhance the gas barrier properties ofthe film, and may also enhance the graphic appeal by adding a highlyreflective surface while eliminating conduction across the balloonsurface. The metal layer may be produced by processes for producingpatterned metal deposits. For example, the use of aluminum or coppervapor deposition with a moving mask, masking bands to shadow the filmsurface, an oil-printing roll producing printed or patterned oil layersplaced on the film surface to prevent adhesion of the aluminum or coppervapors on the film surface. As such, a plurality of individual,physically isolated aluminum or copper deposits may be created.

The discontinuous or patterned, metal layer may be created by variousprocesses. In one embodiment, the moving substrate may be printed withan organic liquid to form a base pattern. A metal layer may be depositedto cover the printed substrate thereby creating a plurality ofcomplementary metal pattern areas covering the printed substrate. Thesubstrate is subsequently heated to vaporize the base pattern leavingthe complementary metal patterns applied to the film. In anotherembodiment, a metal pattern may be created by selective chemicaletching, or printing and etching a metallized film with a 100% metalsurface coverage. The metallized film may be printed with an etchant,such as a caustic material, to selectively remove the metal deposit fromthe film surface in the printed area to leave a complementary metalpattern, washing the etchant from the film surface and drying the filmprior to winding. Alternatively, the metallized film may be printed toform an image with a material resistant to the chemical attack of anetchant. The printed film may be subsequently passed through a bath ofetchant material for a period of time sufficient to remove the metallayer not protected by the etchant resistant material. The etchedmaterial may be washed to remove excess etchant and dried prior towinding.

In a further embodiment, a film may be coated with a water solublevarnish applied over the entire film surface using a rotogravureprinting machine or a similar coater. The film may be vacuum metallizedto deposit a metal layer over the entire surface of the film, coatedwith the varnish. The metallized surface of the film may be printed withclear or pigmented water resistant inks using a rotogravure or similarprinting system to create a printed image. Subsequently, the printedmetallized varnished film may be washed with water to remove the areasnot protected with the water resistant coatings to remove the watersoluble varnish and the metal layer applied to it, followed by drying.As such, a patterned metallized film may be obtained. The film thuscreated has clear un-metallized areas as well as printed areas with themetal layer under the printed image. The printed image may be made ofmulticolored inks or clear inks.

In yet a further embodiment, a patterned metallized film may be preparedwith a complementary metal oxide pattern. A preexisting metallized filmmay be printed with a pattern of hydrophobic ink to the metal surface.The printed, metallized film may be immersed into water heated to atemperature of approximately 80° C. or greater. As such, the warm waterconverts the metal layer not covered by the hydrophobic ink to thenon-conductive metal oxide.

In various embodiments, each of the isolated metallized areas of theinstant invention comprise a two-dimensional pattern of continuousdeposits of the metal layer, which are continuous layers of vapordeposited metal physically separated by clear film areas. The metaldeposits are essentially two-dimensional patterns or islands of,isolated, continuous, conductive deposits of metal, physically isolatedfrom other deposits by physical spacing's of non-conductive areas formedin the metal layer. The films are non-conductive due to the presence ofun-metallized areas surrounding and electrically isolating thetwo-dimensional metal deposits from adjacent metallized areas. Theisolating nonconductive areas may be clear, metal free areas such asthose formed by chemical etching, or from the formation of nonconductiveoxide layers produced on the metallized film. The width of the spacingcreates the loss of conduction and prevents electrical breakdown at adefined voltage applied to the discontinuous metal deposit. The exactdimensions of the non-conductive areas separating the individualconductive areas may be a function of the voltage applied to exposedpattern metallized surfaces and the polymer surface on which the metalis deposited. The dimensions of the non-conductive areas are to bechosen based upon the substrate polymer and the maximum voltage to whichthey are to be exposed. The films produced with a plurality ofindividual, physically isolated metal (e.g., aluminum or copper)deposits are non-conductive over large areas of the film. The brightreflective characteristics are maintained due to the multiplicity ofindividual continuous layers of reflective metal deposits, andelectrical conduction across the surface when exposed to the physicalseparation of the individual physically isolated deposits is prevented.

In further embodiments, a nonconductive polymer film may be depositedonto the reflective film thereby reducing the potential for high voltageelectrical conductance. This nonconductive polymer film may be depositedby an in chamber coating process, via an out of line solution, emulsion,extrusion coating or related printing process, a spray coating processor by an adhesive or extrusion lamination process. In some embodiments,the patterned metal deposition can also be applied to the inner surfaceof a non-conductive balloon film such as the heat sealing layer 214illustrated in FIG. 2. The patterned deposition may be applied inregister to a predefined balloon envelope shape to prevent diminishingthe sealing functions of the inner sealing layer of the balloon envelop.In other embodiments, the deposited pattern can be designed such thatthe gas tight nature of the heat sealing area is not effected.

In various embodiments, the thickness of the films range fromapproximately 0.25 mil (25 gauge, or 6.25 microns) to 4 mil (400 gauge,100 microns). In some embodiments, the thickness of the films rangebetween 0.5 mil (50 gauge, or 12.5 microns) to 3 mil (300 gauge, 75microns). In further embodiments, the thickness of the films rangebetween 0.7 mil (70 gauge, or 18 microns) to 1.5 mil (150 gauge, 38microns). The thickness of the gas barrier layer may be dependent on thestructure of the envelop films, the desired flight times and the barrierpolymer compositions chosen for any particular film design. The filmsmay have a barrier layer thickness ranging from 80% to 25% of the totalfilm thickness, tie layer thicknesses ranging from 10% to 40% of thetotal film thickness and surface sealing layers ranging from 5% to 40%of the total film thickness.

The optimum thickness of the balloons envelope film and total barrierlayer thickness may be determined by the volume of the balloon envelope,the buoyancy produced by the volume of helium and the heliumpermeability requirements based on the flight time requirements. Flighttimes may be determined from loss in buoyancy due to helium permeabilitythrough the films as long as the weight and helium permeability of aballoon film are known. If flight time is specified for a given envelopesize, the required helium permeability may be determined and the barrierstructure (e.g., the selection of polymer, the layer structure, and thebarrier layer thickness) of the envelope film can be selected.

The barrier layer composition, thickness and structure may be determinedby balloon envelope size. Although larger volume balloons may have morebuoyancy than smaller balloons and can lift a larger mass of film thansmaller balloons, the surface area for diffusion of helium is largerwhich requires an increased thickness of the barrier polymer.Consequently, the envelope film weight, determined by the composite filmdensity, thickness and envelop area must vary based on the balloonvolume.

The optimum sealing layer thickness is determined by the sealantpolymers ability to form hermetic seals at a given layer thickness andmay be less sensitive to total envelope thickness. The sealant layerthickness may range from approximately 0.10 mils (2.5 microns) to 1.0mil (25 microns). In some embodiments, the sealant layer thickness mayrange from 0.16 mil (4.0 microns) to 0.75 mil (19 microns). In furtherembodiments, the sealant layer thickness ranges from 0.24 mil (6.0microns) to 0.50 mil (12.5 microns). The thickness of metallized barrierfilms range from approximately 0.25 mil (25 gauge, or 6.25 microns) to 4mil (400 gauge, 100 microns). In some embodiments, the thickness rangesfrom 0.5 mil (50 gauge, or 12.5 microns) to 3 mil (300 gauge, 75microns). In further embodiments, the thickness ranges from 0.7 mil (70gauge, or 18 microns) to 1.5 mil (150 gauge, 38 microns). FIG. 3illustrates an exemplary 7-layer non-conductive films 300 in accordancewith various embodiments of the present application. The illustratednon-conductive balloon film 300 comprises a polyolefin layer 302, afirst adhesive layer 304, a gas barrier core 316, a second adhesivelayer 312, and a heat sealing layer 314. The gas barrier core 316comprises a first EVOH gas barrier layer 306, an adhesive layer 308, anda second EVOH gas barrier layer 310. The EVOH barrier layers 306 and 310may affect the gas barrier properties of the film 300. In particular,the specific ethylene content of a EVOH copolymer may affect the gasbarrier properties of the film 300. The EVOH barrier layers 306 and 310may be determined according to a predetermined level of barrier and flexcrack resistance. In addition, the polyolefin layer 302 and the adhesivelayers 304, 308, and 312 may affect the flex crack resistance. Forembodiments that do not comprise a nylon layer such as the illustratednon-conductive film 300, moisture level of the EVOH may be controlledaccording to the inherent moisture barrier of the polyolefin layer 302and the adhesive layers 304, 308, and 312. In other embodiments, theEVOH layers included in the illustrated film 300 may be replaced bynylon layers.

FIGS. 4A-4B illustrate exemplary 9-layer non-conductive films 400 and450 in accordance with various embodiments of the present application.The film 400 comprises a gas barrier core 420 made of nylon whereas thefilm 450 comprises a gas barrier core 470 made of EVOH. The film 400 issimilar to the 7-layer structure of the film 200 illustrated in FIG. 2where the gas barrier core is composed by alternating gas barrier layers(e.g., a nylon layer) and EVOH layers. The film 450 is similar to the7-layer structure of the film 300 illustrated in FIG. 3 where the gasbarrier core is composed by alternating EVOH layers and adhesive layersor alternating nylon layers and adhesive layers.

FIGS. 5A-5B illustrated exemplary 11-layer non-conductive balloon films500 and 550 in accordance with various embodiments of the presentapplication. The film 500 comprises a gas barrier core 524 comprisingnylon gas barrier layers whereas the film 550 comprises a gas barriercore 570 comprising EVOH gas barrier layers. The film 500 comprises anylon print and barrier layer 502, which is affixed to the polyolefinlayer 506 by the adhesive layer 504. The film 550 comprises a nylonprint and barrier layer 552, which is affixed to the polyolefin layer556 by the adhesive layer 554. The gas barrier core 524 is furtheraffixed to the polyolefin layer 506 by an adhesive layer 508 and the gasbarrier core 574 is affixed to the polyolefin layer 556 by an adhesivelayer 558. The gas barrier core 524 comprises alternating EVOH layersand nylon gas barriers. The gas barrier core 574 comprises alternatingEVOH gas barrier layers and adhesive layers. The gas barrier core 524may be further affixed to the heat sealing layer 522 by the adhesivelayer 520 and the gas barrier core 574 may be further affixed to theheat sealing layer 572 by the adhesive layer 570.

The adhesive layers 504, 508, and 520 may be different from each other,and the adhesive layers 554, 558, 562, 566, and 570 may be differentfrom each other. Each of the adhesive layers may be selected to be theoptimum for affixing the adjacent two layers. The relative thickness ofthe polyolefin layers 506 and 556 may control the placement of thebarrier cores 524 and 574 to the centerline of the films 500 and 550,respectively. In various embodiments, the barrier cores 524 and 574 areplaced closer to the heat sealing layers 522 and 572 than the centerlineof the films 500 and 550, respectively. A thicker polyolefin layer mayprovide a better barrier against moisture because the gas barrier layermay be sensitive to moisture from the environment.

FIGS. 6A-6C illustrate exemplary non-conductive films 600, 620, and 640having a barrier core with a nano-layer structure in accordance withvarious embodiments of the present application. In various embodiments,a barrier core such as the barrier core 216 illustrated in FIG. 2, maycomprise a set of gas barrier layers. Any two gas barrier layers of theset of barrier layers may be separated by a polymer layer. For example,in the illustrated example of FIG. 2, the barrier core 216 comprises afirst gas barrier layer 206 and a second gas barrier layer 210,separated by a polymer layer, that is, the EVOH layer 208. In variousembodiments, at least one barrier layer of the set of barrier layers mayhave a nano-layer structure. For example, the barrier layer having anano-layer structure may comprise a set of sub-barrier layers, where anytwo adjacent sub-barrier layers may be separated by a sub-polymer layer.In one embodiment, a barrier layer may comprise at least eight (8)sub-barrier layers, where the adjacent sub-barrier layers are separatedby a sub-polymer layer. The sub-polymer layer may be a barrier resin ora non-barrier resin.

In the illustrated examples, the non-conductive balloon film 600comprises a barrier core 606 having a nano-layer structure. The barriercore 606 comprises a set of nylon layers and a set of adhesive layers,where the set of nylon layers and the set of adhesive layers arearranged as a nano-structure. In various embodiments, the illustratedbarrier core 606 may have a nano-layer structure of 16 to 64 alternatingnylon and adhesive layers. The nylon material included in the barriercore 606 may be selected according to a predetermined gas barrierrequired such that to control the float time of a balloon.

The non-conductive balloon film 620 comprises a set of EVOH layers and aset of adhesive layers, where the set of EVOH layers and the set ofadhesive layers form a nano-structure. The barrier core 626 may comprisea nano-layer structure of 16 to 64 alternating EVOH and adhesive layers.The EVOH included in the barrier core 626 may be selected according to apredetermined gas barrier required such that to control the float timeof a balloon.

Further embodiments may comprise a barrier core made of nylon and EVOHblending materials. EVOH provide a better gas barrier capability thannylon but the cost of EVOH is higher than the cost of nylon. A materialmade by blending nylon with EVOH (e.g., with a nylon composition of 20%to 40%) may improve the EVOH ductility without compromising the EVOH gasbarrier capabilities. The barrier core 646 may comprise a nano-layerstructure of 16 to 64 nylon and EVOH blended layers.

The non-conductive balloon film 640 comprises a nano-layer barrier core646 comprising a set of alternating EVOH layers and nylon layers. Eachof the set of EVOH layer is a gas barrier layer and each of the set ofnylon layers is a synergistic or adhesive layer. Sandwiching an EVOHlayer between two nylon layers may improve the durability of the EVOHlayer. In addition, a nylon layer may function as a desiccant layer tomaintain the EVOH layer at a lower moisture content thereby maintainingthe gas barrier property of the EVOH layer as a nylon layer absorbs andbinds more moisture than an EVOH layer. Nevertheless, a EVOH layercannot be too thin such that the Nylon layer affects the crystallinedevelopment of the EVOH layer and decrease the EVOH gas barrier layergiving a sudden loss in gas barrier with the increase in the number oflayers.

In some embodiments, a gas barrier core having a nano-layer structuremay be located centrally in a non-conductive balloon film or offcentered towards either of the surfaces. In other embodiments, a gasbarrier core may comprise a set of sub-gas barrier cores. FIG. 7illustrates an exemplary balloon film 700 having a barrier core havingmultiple sub-barrier cores, where each of the sub-barrier core has anano-layer structure in accordance with an embodiment of the presentapplication. The non-conductive balloon film comprises a barrier core720. The barrier core 720 comprises a first barrier core 706 and asecond barrier core 714. The first barrier core 706 and the secondbarrier core 714 are separated by a polyolefin layer 710. The polyolefinlayer 710 may comprise multiple layers of polymers. The first barriercore 706 and the second barrier core 714 each may have a nano-structurewith 16 to 32 alternating EVOH and adhesive layers. In otherembodiments, the first barrier core and the second barrier may have anano-structure with 16 to 32 alternating nylon and adhesive layers.Alternatively, the first nanolayer barrier core may have anano-structure with 16 to 32 alternating Nylon layers while the secondnanolayer barrier core may have a nano-structure with 16 to 32alternating EVOH layers. The first barrier core and the second barriermay each have a nano-structure with 16 to 32 alternating nylon and EVOHlayers.

Various embodiments comprise a biodegradable or bio-based film. In someembodiments, each layer of the non-conductive balloon film isbiodegradable, compostable, or bio-based. The biodegradable film orbio-based film is a polymer film where at least 80% of the polymer filmby weight is derived from a non-petroleum or biorenewable feedstock. Upto about 20% of a biodegradable, compostable, or bio-based film may be apolymer sourced from petroleum. The biodegradable or bio-based films maybe made of materials such as polyhydroxybutyrate-valerate (“PHBV”),polylactide (“PLA”), or polyhydroxy-alkanoate (“PHA”). In someembodiments, a biodegradable or bio-based film may be made of polylacticacid (also known as “PLA.”) The PLA is a compostable, thermoplastic, andaliphatic polyester derived from lactic acid, and may have physicalproperties similar to PET and excellent clarity. The PLA may be producedin a high molecular weight form through ring-opening polymerization oflactide or lactic acid by use of a catalyst and heat. The PLA may bemade from plant-based feedstock (e.g., soybeans, corn, wheat, or sugarbeets) or from the fermentation of agricultural by-products (e.g., cornstarch) or other plant-based feedstock. The PLA can be processed likemost thermoplastic polymers into a film. PLA films degrade into carbondioxide and water at temperatures above its glass transitiontemperature. In one embodiment, the bio-based film layer comprises atleast about 90% polylactic acid.

In some embodiments, the biodegradable or bio-based film is made of PHA,which is a polymer belonging to the polyesters class and can be producedby microorganisms as a form of energy storage. Microbial biosynthesis ofPHA may start with the condensation of two molecules of acetyl-CoA tocreate acetoacetyl-CoA, which may be subsequently reduced tohydroxybutyryl-CoA. Hydroxybutyryl-CoA may be used as a monomer to PHAsuch as polymerize Polyhydroxybutyrate (“PHB”).

Various embodiments including PLA, PHA (e.g., PHB), orpolyhydroxybutyrate-valerate (“PHBV”) can be produced by coextruding thebiodegradable, bio-based polymers into a film sheet in combination witha gas-barrier core. The bio-based films may replace polyolefin resinsincluded in a non-conductive film, such as those used in thesynergistic, the intermediate layers and the surface layers of the film.Various embodiments may be cast or blown or oriented in the machinedirection or the transverse direction. In one embodiment, the bio-basedfilm comprises a biaxially oriented film. In one embodiment, PHBV richblend resin may be coextruded onto a surface of a bio-based film to forma surface layer, upon which graphics may be printed. Heat sealablesurface layers of PHBV, PHB or PLA may also be used to form the heatsealing surface of an non-conductive balloon film. A biodegradable orbio-based film may also be solvable in water and extrudable, such aspolyglycolide or Polyglycolic acid (“PGA”), or similar natural barrierpolymers.

FIG. 8 illustrates an exemplary non-conductive balloon film 800 inaccordance with an embodiment of the present application. Thenon-conductive balloon film 800 comprises a ceramic layer 802, a highbarrier deposition skin 804, a gas barrier core 806, and a heat sealinglayer 808. The gas barrier core 806 may comprise a set of orientednylon, PET, or OPP sheets. The ceramic layer 802 may be materials suchas SiO2, SiOx, Al2O3, CeO2, Ce2O3, or AlOxNy, and the ceramic layer 802may be deposited onto the high barrier deposition skin 804. The highbarrier deposition skin 804 may be the decorating surface of thenon-conductive balloon film 800. The high barrier deposition skin 804may be made of materials such as an amorphous nylon, amorphous PET,EVOH, PET or flame treated HDPE may optimize the barrier properties ofthe ceramic layer 802. The deposition skin 804 may be selected accordingto the materials of the ceramic to provide an optimum surface foroptimizing the gas barrier property of the ceramic selected. In variousembodiments, the ceramic layer 802 may be top coated or laminated. Inanother embodiment, the ceramic layer 802 may be replaced with a metaldeposited layer. The metal-deposited layer 802 may be materials such as,Al, Cu, Ag, Au, Ni.

FIGS. 9A-9E illustrated exemplary non-conductive balloon films 900, 920,940, 960, and 980 in accordance with various embodiments of the presentapplication. The non-conductive balloon film 900 comprises a laminatedfilm layer 902, a lamination layer 904, a metal layer 906, a gas barriercore 908, and a heat sealing layer 910. The metal layer 906 may be alayer of continuous metal deposited on the gas barrier core 908. In oneembodiment, the metal layer 906 is a vapor deposited aluminum layer. Themetal layer 906 may enhance the gas barrier properties of the film 900and may further increase the balloon float time. The laminated filmlayer 902 may be surface or reverse printed, and may be PET or OPPbased. The lamination layer 904 is affixed to the surface of the metallayer 906 by adhesive, thermal, or extrusion lamination. The adhesivesmay be one or two part adhesives, and the extrusion adhesive layer maybe LDPE. The laminated film layer 902 may be affixed to the metaldeposition by using the 12 micron PE extrusion lamination. The laminatedfilm layer 902 may be a non-conductive polymer film and may insulate themetal layer 906. In various embodiments, the thickness of the laminatedfilm layer 902 may be in the range of 8 to 18 microns.

Similar to the non-conductive film 900, the non-conductive films 920 and940 may comprise a metal layer 924 and a gas barrier core layer 926,respectively. The coating layers 922 and 942 may be applied to the metallayer 924 and the metal layer 926, respectively. The coating layer 922or 942 may be a polyolefin extrusion coating layer having a thickness inthe range of 8 to 24 microns. The coating layers 902, 922, and 942 maybe surface printed. Each of the coating layers 902, 922, and 942 may bea solution coated layer using any liquid born film forming polymer andbe applied by coating methods such as gravure, airknife, Myer rod orspray.

The coating layers 902, 922, and 942 may be non-conductive polymer(e.g., a polyolefin film or acrylic polymer) and applied to the metalsurface via liquid solution or emulsion coating or lamination such asextrusion, adhesive or thermal laminations. As such, the non-conductivelayer is directly applied to the metal surface by extrusion coating orliquid coating. The extrusion coating extrudes a molten layer of thepolyolefin onto the metal surface, whereas the liquid coating applies apolymer solution or emulsion and removes the solvent by drying leavingan insulating polymer layer. The metal layer is thereby insulated fromany electrical current by the resistance of the non-conductive polymerlayer deposited on the metal even though the metal layer itself remainsconductive. The composition, thickness and defect concentration of theapplied polymer films determine the electric breakdown of thenon-conductive coating layer.

The films 960 and 980 each comprise a metal deposition 964 and 984,respectively. Further, the surfaces of the metal deposition 964 and 984are treated by adding a non-conductive polymer film 962 and 982,respectively. As such, the films 960 and 980 are insulated. Thenon-conductive polymer films 962 and 982 may be applied as a vapor orcoated as a liquid to the metal coating layer and subsequentlypolymerized by UV, Electron or other actinic radiation within themetallization chamber. The gas barrier may be further enhanced byincluding a second coating layer to the other surface of the metallayer, such as illustrated in FIG. 9E. The gas barrier core layer 988may be deposited with the coating layer 986 prior to the metal layer 964being deposited onto the coating layer 986.

FIG. 10 illustrates an exemplary non-conductive film 1000 in accordancewith an embodiment of the present application. The film 1000 comprises ametal layer 1002 that is deposited onto a surface of the gas barriercore 1004. The metal layer 1002 may be a patterned metal layer such thatthe metal film is discontinuous. Accordingly, the surface of the film1000 is not conductive. The addition of the patterned metal deposit mayenhance the gas barrier properties of the film 1000 by decreasing thearea of surface diffusion from the film. The metal layer may be furthercoated similar to the embodiments illustrated in FIGS. 9A-E to improveits graphics capabilities or to protect the metal deposit layer 1002.The metal layer 1002 may be patterned in a wide range of geometricshapes and carry information such as texts or graphics.

FIGS. 11A-B illustrate exemplary non-conductive films 1100 and 1120 inaccordance with various embodiments of the present application. Thefilms 1100 and 1120 include biodegradable or compostable films tominimize the environmental impact of lost or released balloons. The gasbarrier property of the film 1100 may be enhanced by a barrier primerlayer 1104 applied by coextrusion. The film 1100 comprises a PETG filmskin for high barrier metallization, and the film 1120 comprises aPVOH/EAA inline coated high barrier metallization primer for highbarrier metallization. The gas barrier property of the film 1120 may beenhanced by the application a barrier primer layer 1124 by an inlinecoating process. The heat sealing layers 1108 and 1128 may be amorphousPLA, PHA, PHVB, or other similar materials.

Various embodiments may be produced by coextrusion. Non-conductive filmsmay be produced by cast coextrusion or blown coextrusion. Films mayfurther be oriented to enhance the physical and gas barrier properties.The films are extensible for balloon envelopes of various shapes wheninflated. The embodiments having a nano-layer structure may be producedfrom alternating barrier resin pairs or by alternating a barrier resinand a non-barrier or synergistic layer resin. The synergistic layerresin may be a resin with either a high or a low chemical bonding withthe barrier resin that may enhance a specific mechanical property of thefilm (e.g., a polyolefin, a tie or bonding resin, or a blend of a mix ofpolyolefin and bonding resin.) The primary barrier resin may be nylon,EVOH, or a mix of nylon and EVOH. A primary barrier resin may becopolymers of ethylene and vinyl alcohol with an average ethylenecontent of between 25 mol % to 48 mol %. Other exemplary copolymers mayinclude acrylonitrile copolymers, polyurethane engineering plastics,ethylene vinyl alcohol copolymers, polyvinylidiene chloride, liquidcrystal polymers, amorphous nylons, VINEX poly (vinyl alcohol), andPolyglycolic acid or polymethylpentene resins.

A synergistic layer may comprise a polyolefin, a tie, adhesive, orbonding resin, or a mix of a polyolefin and bonding resin, or a nylon ifused in conjunction with an EVOH barrier layer. Exemplary resins includepolyolefin resins, or copolymers of polyolefins (e.g., polyethylene,polypropylene, or a combination of thereof). A polymer resin mayadditionally include copolymers of polyethylene with minor amounts ofother C₄₋₁₀ olefins, particularly C₄₋₈ polyolefins. In some embodiments,polyethylenes include HPLDPE resins, or LLDPE resins having a density offrom about 0.925 to about 0.945 g/cm³. In some embodiments, polymersinclude polypropylenes such as isotactic, that have a density of fromabout 0.89 to about 0.91 g/cm³. In other embodiments, an adhesive resinis a modified olefinic polymer containing carboxyl groups obtained bycombining chemically (e.g. by addition reaction, graft reaction, etc.)Exemplary olefinic polymers include polyolefins such as polyethylene(low-density, medium-density, high-density), linear low-densitypolyethylene, polypropylene, polybutene, or a copolymer of an olefin anda comonomer copolymerizable (e.g. vinyl esters, unsaturated carboxylicacid esters etc.) Exemplary copolymers include ethylene-vinyl acetatecopolymer and ethylene-ethyl acrylate copolymer. Some embodimentscomprise the ethylene-vinyl acetate copolymer (vinyl acetate content5-55% by weight) and the ethylene-ethyl acrylate copolymer (ethylacrylate concentration 8-35% by weight).

The ethylenically unsaturated carboxylic acid or its anhydride includesethylenically unsaturated monocarboxylic acids, esters thereof,ethylenically unsaturated dicarboxylic acids, mono- or di-estersthereof, and anhydrides thereof. Some embodiments use the anhydrides ofthe ethylenically unsaturated dicarboxylic acids. For example, maleicacid, fumaric acid, itaconic acid, maleic anhydride, itaconic anhydride,monoethyl maleate, monoethyl maleate, diethyl maleate, or methylfumarate may be used. One embodiment uses the maleic anhydride. Theamount of the ethylenically unsaturated carboxylic acid or its anhydrideto be added or grafted to the olefinic polymer. The amount in variousembodiments is generally 0.01-15% by weight. In one embodiment, theamount is 0.02-10% by weight.

In various embodiments, one or more adhesive resins may be used. Theadhesives resins may be used singly, as a mixture of two or morethereof, or blended with other synergistic polymers. As such, variousembodiments provide excellent flexing endurance. In various embodiments,the thickness of each adhesive resin layer is preferably 2-10micro-meters (μm).

As used herein, the terms less than, less than or equal to, greaterthan, and greater than or equal to, may be used herein to describe therelations between various objects or members of ordered sets orsequences; these terms will be understood to refer to any appropriateordering relation applicable to the objects being ordered.

While various embodiments of the present invention have been describedabove, it should be understood that they have been presented by way ofexample only, and not of limitation. Likewise, the various diagrams maydepict an example architectural or other configuration for theinvention, which is done to aid in understanding the features andfunctionality that can be included in the invention. The invention isnot restricted to the illustrated example architectures orconfigurations, but the desired features can be implemented using avariety of alternative architectures and configurations. Indeed, it willbe apparent to one of skill in the art how alternative functional,logical or physical partitioning and configurations can be implementedto implement the desired features of the present invention. Also, amultitude of different constituent module names other than thosedepicted herein can be applied to the various partitions. Additionally,with regard to flow diagrams, operational descriptions and methodclaims, the order in which the steps are presented herein shall notmandate that various embodiments be implemented to perform the recitedfunctionality in the same order unless the context dictates otherwise.

Although the invention is described above in terms of various exemplaryembodiments and implementations, it should be understood that thevarious features, aspects and functionality described in one or more ofthe individual embodiments are not limited in their applicability to theparticular embodiment with which they are described, but instead can beapplied, alone or in various combinations, to one or more of the otherembodiments of the invention, whether or not such embodiments aredescribed and whether or not such features are presented as being a partof a described embodiment. Thus, the breadth and scope of the presentinvention should not be limited by any of the above-described exemplaryembodiments.

Terms and phrases used in this document, and variations thereof, unlessotherwise expressly stated, should be construed as open ended as opposedto limiting. As examples of the foregoing: the term “including” shouldbe read as meaning “including, without limitation” or the like; the term“example” is used to provide exemplary instances of the item indiscussion, not an exhaustive or limiting list thereof; the terms “a” or“an” should be read as meaning “at least one,” “one or more” or thelike; and adjectives such as “conventional,” “traditional,” “normal,”“standard,” “known” and terms of similar meaning should not be construedas limiting the item described to a given time period or to an itemavailable as of a given time, but instead should be read to encompassconventional, traditional, normal, or standard technologies that may beavailable or known now or at any time in the future Likewise, where thisdocument refers to technologies that would be apparent or known to oneof ordinary skill in the art, such technologies encompass those apparentor known to the skilled artisan now or at any time in the future.

The presence of broadening words and phrases such as “one or more,” “atleast,” “but not limited to” or other like phrases in some instancesshall not be read to mean that the narrower case is intended or requiredin instances where such broadening phrases may be absent. The use of theterm “module” does not imply that the components or functionalitydescribed or claimed as part of the module are all configured in acommon package. Indeed, any or all of the various components of amodule, whether control logic or other components, can be combined in asingle package or separately maintained and can further be distributedin multiple groupings or packages or across multiple locations.

Additionally, the various embodiments set forth herein are described interms of exemplary block diagrams, flow charts and other illustrations.As will become apparent to one of ordinary skill in the art afterreading this document, the illustrated embodiments and their variousalternatives can be implemented without confinement to the illustratedexamples. For example, block diagrams and their accompanying descriptionshould not be construed as mandating a particular architecture orconfiguration.

What is claimed is:
 1. A method of creating a film for lighter than airballoons, comprising depositing a metal layer on a first surface of asubstrate; coating the metal layer with a varnish; printing on thevarnish such that a set of regions of the varnish is not covered by anink; and removing the set of regions of the varnish.
 2. The method ofclaim 1, wherein the substrate comprises a gas barrier core comprising aset of gas barrier layers and adhesive layers, the gas barrier corehaving a first surface and a second surface, the gas barrier corecomprising a set of polymeric gas barrier layers, wherein thediscontinuous metal layer is the first surface.
 3. The method of claim2, further comprising affixing a heat sealing layer to the secondsurface of the gas barrier core.
 4. The method of claim 1, wherein theink is water resistant.